The present invention relates to a low frequency medical device and method for the sealing of tissue puncture wounds after surgical procedures.
With improvement in medical devices and procedures, it is increasingly becoming possible to avoid the trauma and complications caused by open surgery using various transcatheter techniques. Some examples of these procedures include; angiography, percutaneous transluminal coronary angioplasty, stenting, atherectomy and catheter ablation. These new methods are being developed because they offer significant benefits with respect to patient recovery, potential complications and cost. The early discharge of patients undergoing these elective and interventional procedures hinges on the lack of bleeding complications at the access site after the procedure sheath is removed from the artery. The size of the access route, coupled with the routine administration of anticoagulants, creates a strong need to stop bleeding at the puncture site as quickly as possible. However, hemostasis must be achieved without producing clotting in the vessel just treated in order to prevent a potentially fatal myocardial infarction or thrombosis.
Simple compression is currently the standard of care for managing vascular access sites following interventionial cases. Compression includes the use of hand pressure, clamps and/or sand bags. To begin with, anticoagulant therapy typically has to be discontinued up to four hours prior to vascular closure in order to permit the patient's clotting capability to improve. During this period the patient must remain immobilized to prevent bleeding with the sheath in place. Upon sheath removal a nurse or technician holds direct pressure on the site for at least 30 minutes until thrombus forms to seal the access site. Once hemostasis has been achieved the patient must remain motionless for a period of time that may range from 4 to 24 hours to minimize the risk of dislodging the clot. Furthermore, the direct pressure necessary to close the vessel puncture may restrict blood flow within the vessel itself, causing unwanted complications to the patient.
To overcome the problems associated with manual compression, the use of a variety of alternative methods have been developed. These systems commonly known include heat sealing, lasers, suture based systems, or various types of plugs or glues. Plugs may be made in many different shapes and may be created from a variety of materials. No matter what the material or the shape of the plug, accurate placement of the plug is desirable. Placement is particularly import with prior art plug systems which use some portion of the patient's blood to form a clot or other obstructions.
Prior art closure systems include devices such as the one described in U.S. Pat. No. 5,626,601 to Gershoney. This particular system uses a balloon which can be inflated to prevent the closure material from entering the vessel. Once the plug material has been injected into the vascular access site and partially solidifies, the balloon is deflated and pulled through the plug material. Another prior art closure device invented by Kensey and described in U.S. Pat. No. 5,676,689, uses a biodegradable backstop to prevent a plug from entering the vessel.
Prior art references that describe cauterization sealing of the vessel opening include U.S. Pat. Nos. 4,929,246; 5,810,810; and 5,415,657, which disclose the use of a laser or of radio-frequency (RF) energy that is transmitted to the blood vessel through a catheter to thermally fuse or weld the punctured tissue together. U.S. Pat. No. 6,656,136 to Weng et al, describe the use of high intensity focused ultrasound to cauterize the wound opening.
The prior art devices do not effectively resolve the problems associated with alternative mechanisms to the use of compression for vascular sealing and do not provide the benefits of the present invention as described below.